Yeah, it's possible. My zombie XP farm causes the zombies to fall 22 blocks so they're only 1-3 punches away from death (a few die in the fall for some reason). I let them build up for half an hour or so, and when I come back there's hundreds of zombies waiting to be punched in the knees. I could also use splash potions on them to kill the whole group in one go, but I haven't tested that yet.

Click to expand...

Ah, but you still have to attack them yourself to get the XP. I suppose the traps do make it a bit too easy.

On the other hand, people have been exploiting whatever game mechanics are available since day one.

You might like Robert's server then, Sheep. I'd call it a hybrid of survival mode with creative mode sensibilities. We don't lose anything when we die, and we're heavy on exploration, mining and building. Perhaps most important of all is the fact that there are no creepers on the server, as we find them too destructive in general.